<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var n = prompt("how much time after today?"), week = 5 + n % 7;
        if (week > 7) {
            week -= 7;
        }
        switch (week) {
            case 1:
                week = "monday";
                break;
            case 2:
                week = "tuesday";
                break;
            case 3:
                week = "Wednesday";
                break;
            case 4:
                week = "Thursday";
                break;
            case 5:
                week = "Friday";
                break;
            case 6:
                week = "Saturday";
                break;
            case 7:
                week = "Sunday"
        }
        alert('today is ' + week)
    </script>
</body>
</html>